Each work may comprise different editions, translations, printings, audio versions, etc. Members are encouraged to add publicly visible reviews, descriptions, Common Knowledge and other information about a work; ratings, collections and tags help categorization. Discussion in the forums is also encouraged.

Items are classified using the Melvil Decimal System, based on the out-of-copyright 1922 edition of the Dewey Decimal Classification with modifications for standard spelling of division names (as opposed to the original names, which were spelled in accordance with Dewey's advocated spelling reforms), and modernised terminology.[6]

In 2016 LibraryThing launched TinyCat, an OPAC designed for the cataloging and circulation of libraries of up to 20,000 items.[10] TinyCat is marketed towards small independent libraries, such as religious institutions, schools, community centers, and academic departments, as well as individuals.[11]

LibraryThing is majority owned by founder Tim Spalding.[12] Online bookseller AbeBooks (now owned by Amazon) bought a 40% share in LibraryThing in May 2006 for an undisclosed sum.[13] In January 2009, Cambridge Information Group acquired a minority stake in the company, and their subsidiary Bowker became the official distributor to libraries.[12]

At the end of June 2006, LibraryThing was subject to the Slashdot effect from a Wall Street Journal article.[14] The site's developers added servers to compensate for the increased traffic. In December of the same year, the site received yet more attention from Slashdot over its UnSuggester feature, which draws suggestions from books least likely to appear in the same catalog as a given book.[15]